WHY DOES PHENYLALANINE DO HARM IN PKU?

Excess amino acids can compete with both the outward and inward transport of endogenous amino acids in various tissues.     

An increase in polymorphonuclear leucocyte chemotaxis accompanied by a change in the membrane fluidity with age during childhood.

Leucocyte membrane fluidity affects cell deformability as well as the accessibility of receptors and the degree of their exposure on the membrane. These effects modulate the subsequent cellular responsiveness. We have assayed membrane fluidity of polymorphonuclear leucocytes of children, using an excimer-forming lipid technique in flow cytometry, and evaluated its relation to their chemotaxis to a formyl peptide. We report that membrane fluidity and chemotaxis of polymorphonuclear leucocytes are increased with age. These findings may have important implications for the physiological processes in polymorphonuclear leucocyte motility during childhood.     

苯丙氨酸及其代谢物对P19细胞神经分化的影响

探讨苯丙氨酸及其代谢物对P19细胞分化的影响及机制。实验各组从P19细胞神经分化诱导期开始分别加入苯丙氨酸、苯乙酸和苯乳酸 ,观察神经分化期细胞形态 ,MTT法检测神经分化期细胞存活率和LDH漏出量的变化 ,并通过流式细胞仪检测诱导后细胞周期有无变化。结果显示 :苯丙氨酸及其代谢物可使P19神经元肿胀、崩解 ,神经突起纤细且突起数少 ,可降低P19细胞存活率 ,但对LDH漏出量并无影响 ,对诱导后的P19细胞周期也无影响。以上结果提示 ,苯丙氨酸及其代谢物可干扰P19细胞的神经诱导过程 ,母源性苯丙酮尿症中枢神经系统损伤可能与其在脑发育早期阶段神经诱导及分化过程中受到高苯丙氨酸及其代谢物影响有关。     

The Origin of Red Blood Cell Biopterin

Data are presented to support the hypothesis that the biopterin content of red blood cells arises during erythropoiesis. Only when the plasma concentration rises above the erythrocyte concentration of biopterin is there likely to be diffusion into the cell.     

Frailty Status in Older Adults Is Related to Alterations in Indoleamine 2,3-Dioxygenase 1 and Guanosine Triphosphate Cyclohydrolase I Enzymatic Pathways

Background

Frailty is a multidimensional syndrome correlated to the loss of homeostasis and increased vulnerability to stressors, which is associated with increase in the risk of disability, comorbidity, hospitalization, and death in the elderly. It is based on the interplay of physiological, psychological, social, and environmental factors.

串联质谱检测苯丙氨酸浓度在筛选新生儿苯丙酮尿症中的应用

探讨串联质谱法(MS/MS)在检测苯丙氨酸浓度在诊断新生儿遗传代谢性疾病——苯丙酮尿症中的临床应用价值。利用MS/MS分析了9000 例新出生婴儿全血标本中苯丙氨酸(Phe)和酪氨酸(Tyr)的浓度,计算两者的比值。MS/MS分析的Phe的线性范围为25.3~898.5 mol/L, Phe的平均回收率为97.8%, 批内变异系数(CV)为3.85%,批间变异系数CV为4.53%;Tyr的线性范围为39.60~260.07 mol/L, Tyr的平均回收率为96.5%,批内变异系数(CV)为4.25%,批间变异系数CV为5.83%。MS/MS法能够比较灵敏,特异的检测血中 Phe和Tyr的浓度,可以满足对新生儿苯丙酮尿症的筛查及诊断的需要,具有极高的临床应用价值。     

N-9,10-蒽醌-2-甲酰基苯丙氨酸治疗大鼠痛风性关节炎的作用及机制

目的 探究N-9,10-蒽醌-2-甲酰基苯丙氨酸(NAY)对尿酸钠(MSU)所致痛风性关节炎(GA)大鼠的作用及机制。方法 将雄性SD大鼠随机分为7组,每组8只,即正常组、模型组、NAY低(20 mg·kg^-1)、中(40 mg·kg^-1)、高剂量组(80 mg·kg^-1)、秋水仙碱组(0.8 mg·kg^-1)和别嘌呤醇组(10 mg·kg^-1),通过关节腔内注射MSU晶体建立大鼠急性GA模型,各组灌胃给药5 d,给药第3天造模。将原代培养的大鼠腹部巨噬细胞分成空白组、模型组、NAY组、MCC950组和联合给药组。软尺测量大鼠踝关节周长并计算大鼠关节肿胀度;检测大鼠血清尿酸(UA)、肌酐(CRE)和尿素氮(BUN)含量;HE染色观察大鼠踝关节滑膜组织病理切片;检测各组血清、关节滑膜和细胞上清液中肿瘤坏死因子-α(TNF-α)和白介素-1β(IL-1β)的含量;并检测各组关节滑膜和细胞中NOD样受体热蛋白结构域相关蛋白3(NLRP3)、凋亡相关斑点样蛋白(ASC)和半胱氨酸天冬氨...     

Dietetic Management of Adults with Phenylketonuria (PKU) in the UK: A Care Consensus Document

There is an increasing number of adults and elderly patients with phenylketonuria (PKU) who are either early, late treated, or untreated. The principal treatment is a phenylalanine-restricted diet. There is no established UK training for dietitians who work with adults within the specialty of Inherited Metabolic Disorders (IMDs), including PKU. To address this, a group of experienced dietitians specializing in IMDs created a standard operating procedure (SOP) on the dietetic management of adults with PKU to promote equity of care in IMD dietetic services and to support service provision across the UK. The group met virtually over a period of 12 months until they reached 100% consensus on the SOP content. Areas of limited evidence included optimal blood phenylalanine reporting times to patients, protein requirements in older adults, management of weight and obesity, and management of disordered eating and eating disorders. The SOP does not include guidance on maternal PKU management. The SOP can be used as a tool for training dietitians new to the specialty and to raise the standard of education and care for patients with PKU in the UK.